Would a Dragonborn commoner have stats of (Str 11, Dex 9, Con 9, Int 9, Wis 9, Cha 10) due to the base being human which have a +1 to all stats or (Str 12, Dex 10, Con 10, Int 10, Wis 10, Cha 11) by just adding the Dragonborn stats to the commoner template?
The stat blocks were definitely not designed with the assumption that they get -1 in all stats if they are a different race... NPC stat blocks don't have any race assigned to them, it would be more correct to +1 all abilities when you specify it is human.
But really it doesn't matter. Unless you want the NPC to have unique stats, just leave it be.
The Breath Weapon, Damage Resistance, Draconic Ancestry and Languages all get added, consider that the no brainer. This is more for Template NPC/Monster builds. I use the commoner as the base since it is bare minimum and is typically used for a human build. By adjusting the (arguably insignificant) stats up or down, or just leaving them the same and adding "features", is more a personal debate about which would be more, for lack of a better word, correct.
Would a Dragonborn commoner have stats of (Str 11, Dex 9, Con 9, Int 9, Wis 9, Cha 10) due to the base being human which have a +1 to all stats or (Str 12, Dex 10, Con 10, Int 10, Wis 10, Cha 11) by just adding the Dragonborn stats to the commoner template?
You can do either, but I would do neither. I’d leave ability scores alone but give the commoner the dragonborn breath weapon if it really matters.
The stat blocks were definitely not designed with the assumption that they get -1 in all stats if they are a different race... NPC stat blocks don't have any race assigned to them, it would be more correct to +1 all abilities when you specify it is human.
But really it doesn't matter. Unless you want the NPC to have unique stats, just leave it be.
The Breath Weapon, Damage Resistance, Draconic Ancestry and Languages all get added, consider that the no brainer. This is more for Template NPC/Monster builds. I use the commoner as the base since it is bare minimum and is typically used for a human build. By adjusting the (arguably insignificant) stats up or down, or just leaving them the same and adding "features", is more a personal debate about which would be more, for lack of a better word, correct.
Sorry it took so long to post this. I was lazy and didn't feel like digging it up.
The DMG has templates for NPC stat blocks as different races. Here is dragonborn:
For reference, it's in the Dungeon Master's Workshop, Creating a Monster, NPC Stat Blocks.
Helpful rewriter of Japanese->English translation and delver into software codebases (she/e/they)